Hydrogen is commonly used in the Haber process for making ammonia. It is also used in various other industrial processes, such as the reduction of oxide ores, the refining of petroleum, the production of hydrocarbons from coal, and the hydrogenation of vegetable oils. There has also been considerable interest in developing a “hydrogen energy economy” in which hydrogen is electrochemically combined with oxygen in a fuel cell to produce electricity. Producing power using fuel cells offer a number of advantages over conventional means such as internal combustion engines. For example, fuel cells produce energy through electrochemical conversion, instead of combustion, and thus harmful emissions tend to be very low, or zero if pure hydrogen is used. Also, fuel cells can produce power at efficiencies that are much higher than conventional power systems such as the internal combustion engine.
While hydrogen is the most abundant element in the universe, pure hydrogen (H2) rarely occurs naturally on Earth. Instead, it is found in other compounds such as hydrocarbons and water. The most common process for producing hydrogen is by steam reforming natural gas. It can also be made by the Bosch process and by electrolysis of water. Reforming natural gas or other hydrocarbons is a complex process that can produce undesirable byproducts such as carbon dioxide and nitrous oxides. Electrolysis is an energy intensive process that and can involve complex, bulky and costly equipment to produce hydrogen in large quantities.
Another method of extracting hydrogen from water involves chemically reacting water with a metal (“water split reaction”). For example, it has long been known that hydrogen gas can be produced in a chemical process utilizing an alkali metal or metal hydride reacted with water.
Other metals are also known to produce hydrogen when reacted with water; for example, U.S. Pat. No. 6,440,385 (Chaklader) discloses a method of producing hydrogen from water by submerging a mechanical mixture of aluminum oxide(s) and/or aluminum hydroxide(s) and aluminum metal in water. U.S. Pat. No. 6,582,676 (Chaklader) discloses a method of producing hydrogen by reacting a metal selected from the group consisting of aluminum, magnesium, silicon, and zinc, with water in the presence of an effective amount of a catalyst at a pH of between 4 and 10. The catalyst (promoter) is selected to prevent or slow down deposition of the reaction products on the metal that tend to passivate the metal.
None of the known methods and apparatuses for producing hydrogen by a water-split reaction provides a low cost, efficient solution for providing hydrogen on demand. In particular, neither U.S. Pat. Nos. 6,440,385 nor 6,582,676 disclose a practical, cost-effective and efficient apparatus for generating and collecting pressurized hydrogen on demand according to the methods taught in those patents.